averello/linux-stable-mirror
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2026-09-22 09:34:56 +02:00
Code Issues Packages Projects Releases Wiki Activity

sctp: reject stale cookies with mismatched verification tags

Browse Source 
commit 9d8da8e0a9 upstream.

sctp_unpack_cookie() skips cookie expiration checks whenever an
association already exists.  This is broader than the exception in
RFC 9260 Section 5.2.4.

For an existing association, Section 5.2.4 permits an expired State
Cookie only when both Verification Tags in the cookie match the current
association.  Otherwise, the packet SHOULD be discarded and a Stale
Cookie ERROR MUST be sent.

The broad check lets an expired Action A restart cookie reach
sctp_sf_do_dupcook_a().  In a runtime test with the default 60 second
cookie lifetime, replaying such a cookie after 65 seconds returned a
COOKIE-ACK and restarted the association.

Check cookie expiration unless both Verification Tags match.  This
preserves the Action D exception for a lost COOKIE ACK while rejecting
expired cookies in all other cases.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20260723225623.2658868-1-yangyx22@mails.tsinghua.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yuxiang Yang
2026-08-09 20:21:55 +02:00
committed by Greg Kroah-Hartman
parent 49e5b25a0b
commit 61baa5020b
1 changed files with 7 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/sctp/sm_make_chunk.c
+7 -4
View File
@@ -1821,9 +1821,9 @@ no_hmac:
goto fail;
}
/* Check to see if the cookie is stale. If there is already
* an association, there is no need to check cookie's expiration
* for init collision case of lost COOKIE ACK.
/* Check to see if the cookie is stale. RFC 9260 Section 5.2.4
* exempts an expired cookie only when both Verification Tags match
* the current association.
* If skb has been timestamped, then use the stamp, otherwise
* use current time. This introduces a small possibility that
* a cookie may be considered expired, but this would only slow
@@ -1834,7 +1834,10 @@ no_hmac:
else
kt = ktime_get_real();
if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
if ((!asoc ||
asoc->c.my_vtag != bear_cookie->my_vtag ||
asoc->c.peer_vtag != bear_cookie->peer_vtag) &&
ktime_before(bear_cookie->expiration, kt)) {
suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
__be32 n = htonl(usecs);